Eight people were arrested yesterday in Allenstown and Pembroke for dealing heroin and cocaine in a drug sweep that followed a months-long investigation by state and local authorities, officials said.

The arrests began yesterday afternoon and lasted through the early evening. Members of the state’s Drug Task Force raided several residences, seizing at least $10,000 and a “considerable” amount of each drug, Pembroke police Chief Dwayne Gilman said.

“This is a huge hit for Pembroke,” Gilman said.

The investigation began nearly a year ago when Pembroke officials received complaints about one of the suspects, James Wadleigh, 51, of 197 Main St., Gilman said. Wadleigh is accused of overseeing a drug ring spanning both towns and manned by the other suspects. Gilman said more arrests are expected, either later today or early next week.

The seven other suspects, including two 18-year-old men, are said to have distributed the drugs through various methods – hand-to-hand, out of cars and residences. “These are very transient people,” Gilman said.

The task force and state police conducted an undercover inquiry into the enterprise for the past four to six months, Gilman said.